PTL 1 discloses a technique which can further simplify a structure, and which aims to form a substantially horizontal access floor even if an irradiation unit for extracting a particle beam is located at any position. The technique includes a rotating gantry in which a particle beam irradiation unit for extracting the particle beam is installed, an annular frame that is supported inside the rotating gantry so as to be relatively rotatable, a fixed annular frame that is disposed to face the annular frame, a co-rotation preventing mechanism that comes into contact with both the annular frames so as to prevent co-rotation of the annular frame rotated due to the rotation of the rotating gantry, and a bendable moving floor that is disposed between the annular frames, that movably engages with the annular frames so as to cause a lower side to be substantially horizontal, and that further moves due to the rotation of the rotating gantry.
In addition, PTL 2 discloses the following technique. In a case where an irradiation target is irradiated with beams in a plurality of directions, in order to reduce the cost, an irradiation nozzle unit configured to include a wobbler magnet, a scatterer, a range modulator, a patient collimator, and a patient bolus is shared in use with a plurality of irradiation ports for outputting a charged particle beam to the irradiation target in the plurality of directions.